More particularly, the invention mainly relates to a nanofabrication installation comprising:                a sample holder for receiving a sample having a surface,        a mask for forming the sample comprising                    a lower face oriented towards the sample holder,            an upper face opposite to the lower face and arranged for receiving a particle beam emitted by a source in the direction of the sample holder to form the sample,            and at least one through-opening between the upper and lower faces, arranged to allow a portion of said particles to pass through it in the direction of the sample holder,                        a device for near-field detection arranged for detecting a desired relative position of said mask and said sample,        a displacement device arranged for generating a relative movement of said mask and said sample holder in order to position the mask and the sample in said desired relative position, independently of the relative position of the source and the mask.        
Document U.S. Pat. No. 6,313,905 describes an example of an installation of this kind. An evaporative source emits clusters, droplets or particles of matter, through an opening formed in the cantilever of an atomic force microscope (AFM), which is used for monitoring a position of the mask relative to the sample during deposition through the opening.
However, such a device is not completely satisfactory. Indeed, studies showed that such installation presented problems of reproducibility in the formation of a deposit on the sample surface. In fact, the user has no control over the evaporated particles once they have been emitted by the source. Consequently, after deposition it is necessary to verify whether the surface has been formed in the desired manner, for example by imaging the surface.